1. Field of the Invention
This invention relates to a capsule for feeding a chemical agent into the phloem layer of a tree or into other wooden elements, such as a telephone pole, a window frame or sill, studs or other elements used in housing construction or the like, etc. The chemical agent may be a herbicide, if the treatment is designed to kill a tree, a fungicide or other medicant or nutrient, if the treatment is designed to cure a tree from a disease or deficiency, or a wood preservative or insecticide, etc., if the treatment is used in some other type of wooden element.
2. Description of Related Art
The prior art relating to implantation treatments typically involves either injection of a cartridge into a tree without preparing a pre-drilled hole in the tree, or implantation of a capsule in a pre-drilled hole in a tree. Examples of prior art devices for such treatment are set forth below.
U.S. Pat. No. 3,691,683 discloses a cartridge containing a chemical liquid agent where the cartridge is hammered into a tree so that it fractures upon impact. However, the cartridge is inserted only half-way in the tree. Therefore, upon fracture, much of the liquid agent is wasted on the surface of the tree, where it also presents a hazard to the person making the injection.
U.S. Pat. No. 4,308,689 discloses a tree treatment capsule for insertion into a pre-drilled hole in a tree. The capsule is made of a frangible material and contains a liquid agent so that an impact force applied to an end cap of the capsule causes breaking of the capsule. This known capsule is disadvantageous since it begins to break near the bore opening. The capsule thus presents the risk that the liquid agent will be exposed to areas outside of the bore opening. The end cap of the known capsule also requires a very complicated structural design which renders the capsule expensive to manufacture.